This allows it to create two queues which, generally, works well
I flew STN-SNN-STN last Wed to meet someone. (I paid a whopping £2.42 including taxes and card fee.)
I was impressed with FR's two very clear queue areas at both STN and SNN: one for those with priority boarding, one for those without. It worked very effectively.
I'm flying FR BRS-DUB-BRS next Tue, so I'll see what it's like at those two airports.